Hi
I can't recommend any Jaco or Claypool because I am not familiar enough with their music, but Rush (Geddy) is a band I am totally into.
I would recommend YYZ from Moving Pictures which is a instrumental and Big Money from Power Windows.
Also you might want to check out Billy Sheehan especially the song Shy Boy from David Lee Roths Eat Em and Smile Disc and Steve Harris from Iron Maiden, songs like Aces High, Run to the Hills.
Their are many great players, enjoy the music.

Pick up Marvin Gaye's "What's Going On." I have the Deluxe Edition and it is absolutely incredible. It has the original LP mix, the Motown Detroit mix, a whole live concert, and other singles. This is one of my favorite albums of all time and James Jamerson's playing is astoundingly good.

A great bass line doesn't need to be 'technically prohibitively difficult' to be a great line. I love Noel Redding's runs in the Jimi Hendrix Experience's Hey Joe, as well as Paul McCartney's bass line in Lady Madonna. Heck, most of McCartney's lines.

I would recommend, as far as single songs go:
Jaco Pastorius - Portrait of Tracy or Donna Lee
Les Claypool (as in Primus) - Tommy the Cat
Les Claypool (as in Oysterhead) - Mr. Oysterhead
And one of the most impressive:
Victor Wooten - Classical Thump

For Geddy Lee, everyone's always so quick to say, YYZ... bleh... I'll suggest some OTHERs...
Spirit of the Radio
Distant Early Warning
Freewill - the live version from Exit.. Stage Left
In fact, I'd suggest you just buy the CD, Exit.. Stage Left